Flashcards in ToB - Introduction Deck (21)
What is a tissue?
A collection of cells, specialised to perform a particular function.
What are the 4 types of tissue?
What is a smear biopsy and what can it be used on?
Collecting cells by spontaneous/mechanical exfoliation then smearing on a slide.
What is curettage and what is it used on?
Removing tissue via a 'scoop'.
The endometrial lining of the uterus.
What is needle and what is it used for?
Put needle into tissue and removes a sample of cells.
Breast, brain, liver.
What is direct incision and what is it used for?
A sample of the tissue of interest is directly cut into and removed.
Mouth, larynx, skin.
What is endoscopic biopsy and what is it used for?
Tissue sample is removed via instruments through an endoscope.
What is transvascular biopsy and what is it used for?
Heart and liver.
Why are slides set in wax?
Stop self lysing.
Stop attack of bacteria.
This cross links macromolecules.
What chemicals are used to fix slides?
Formaldehyde or glutaraldehyde.
How is a wax set slide dehydrated?
Using ethanol then xylene.
Why does shrinkage occur?
Due to the dehydration and rehydration of the sample during fixation.
What does haematoxylin and eosin stain?
Haematoxylin - acidic components purple.
Eosin - basic components pink.
What does periodic acid-Schiff stain?
It stains carbohydrates and glycoproteins magenta.
What is phase contrast microscopy?
Exploits the interference effects produced when 2 light waves combine.
Enhances the image of unstained cells.
What is dark field microscopy?
Excludes any unscattered light/electron beam from the image.
Works on live and unstained samples.
Has a dark background.
What is fluorescence microscopy?
Targets the molecule of interest with a fluorescent antibody.
Can use multiple fluorescence targets on one specimen.
What is confocal microscopy?
The tissue is labelled with one or more fluorescent probes.
Can view live specimens and build up a 3D image from a series of 2D ones. Eliminates out of focus flare from thick fluorescently labelled specimen.
What is the difference between SEM and TEM?
SEM reflects electrons from the specimen, TEM allows them to pass through the specimen.
How can you tell images from SEM and TEM apart?
SEM appears more like a photo, TEM like a micrograph.